About the @chunk attribute

The @chunk attribute specifies how a processor should split or combine source DITA documents into alternate organizational schemes for rendering purposes. This means that the @chunk attribute is only relevant when the organization of source DITA documents has an effect on the organization of published documents.

The @chunk attribute only operates on topics and nested topics. It does not operate on other topic content, such as sections.

The @chunk attribute is composed of a single token without any white space. DITA defines the following tokens for the @chunk attribute:

combine
Instructs a processor to combine the referenced source documents for rendering purposes. This is intended for cases where a publishing process normally results in a single output artifact for each source XML document.
split
Instructs a processor to split each topic from the referenced source document into its own document for rendering purposes. This is intended for cases where a publishing process normally results in a single output artifact for each source XML document, regardless of how many DITA topics exist within each source document.

Applications can use custom tokens for the @chunk attribute.

The @chunk attribute does not cascade.

The following rules apply to all values of the @chunk attribute:
  • When the source document organization has no effect on published output, such as when producing a single PDF or EPUB, processors MAY ignore the @chunk attribute.
  • When the @chunk attribute results in more or fewer documents based on the combine or split tokens, the hierarchy of topics within the resulting map and topic organization SHOULD match the hierarchy in the original topics and maps.
  • When the @chunk attribute results in more or fewer documents, processors MAY create their own naming schemes for those reorganized documents.
  • The @chunk attribute values apply to DITA topic documents referenced from a map. Processors MAY apply equivalent processing to non-DITA documents.